Tor N. Johnson

This plugin enables themes to specify a different single.php template based on post category. As posts can have multiple categories assigned, it uses the following to select which possible custom template to use:
1) Categories directly assigned 
 — Check for extant single-CATEGORYID.php files and prioritize based on category order 
2) Parents of categories 
 — Parents are checked based on category order of the directly assigned categories.
Note, the above assumes that there’s a category order plugin installed. If the categories are NOT in a specific order AND there are multiple categories assigned per post then the template selection will be left up to the server. Naturally, if there is only category assigned per post (or only one possible template per post), then there will be no issue.
<h3>Requirements</h3>

Custom-Single

Enables themes to support custom single.php templates per category in the form single-CATEGORYID.php.

vegacorp

Jose Vega

Green Jay Media

<ul>
<li>
Easily create custom page templates for any theme.
</li>
<li>
Do you want to use a WordPress theme that doesn´t have a full width page template? Add any template to your theme with WP Page Templates
</li>
<li>
You can add a left and/or right sidebar. You can even add above or below main content.
</li>
</ul>
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<h4>Features</h4>
<ul>
<li>
Add left sidebar to pages
</li>
<li>
Add right sidebar to pages
</li>
<li>
Add left and right sidebar to pages
</li>
<li>
Add sidebar below the content
</li>
<li>
Add sidebar above the content
</li>
<li>
And more…
</li>
</ul>
<h4>Go Premium</h4>
If you need more features, our premium version allows you to:
<ul>
<li>
Hide header and footer for Landing Pages
</li>
<li>
Hide header and footer for WooCommerce Products
</li>
<li>
Hide header and footer for Events or any Post Type
</li>
<li>
Create full width posts
</li>
<li>
Create full width WooCommerce products
</li>
</ul>
<a href="https://wppagetemplates.com/premium-upgrade/?utm_source=wp.org&utm_medium=web&utm_campaign=free-plugin" rel="nofollow ugc">Try the premium plugin for free for 7 days</a>

WP Page Templates

Create full width pages, add left or right sidebars, add above or below content sidebars.

Custom-Single vs WP Page Templates